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Correct ANSWER is (a) True

The best I can explain: Many cells of a PLANT are occupied by 90% of the vacuole. Most of the cell’s sugars, proteins and other biomolecules are STORED temporarily in the vacuole.

Right answer is (b) False

For explanation I would say: ROUGH endoplasmic reticulum imports the proteins cotranslationally i.e. while they are being synthesized. Organelles LIKE peroxisomes and mitochondria import the proteins posttranslationally, after their COMPLETE synthesis on FREE ribosomes in the cytosol.

Right OPTION is (b) accessory protein

The best I can EXPLAIN: Dynamin is a large GTP^–binding accessory protein that AIDS in the release of clathrin^–coated VESICLE from the membrane on which it is formed.

Correct OPTION is (c) COPI-coated vesicles

For explanation I would say: The COPI-coated transport vesicles operate in the retrograde direction and are responsible for retention of proteins that reside in the ER membrane or lumen and are accidentally carried away by the Golgi complex. Such proteins possess retrieval signals at their C-terminus which is CAPTURED by RECEPTORS on the COPI-coated vesicles, which transport them back to the ENDOPLASMIC reticulum.

Right answer is (a) neutrophils, macrophages

Explanation: Neutrophils and macrophages are the phagocytic CELLS that INGEST potentially DANGEROUS microbes; the microbes are then inactivated by the LOW pH of lysosomes PRESENT in these cells followed by their enzymatic digestion.

The correct choice is (C) G-protein

To explain: Among COPII PROTEINS, SAR1 is a G-protein which initiates vesicle formation and regulates the assembly of the vesicle COAT. G-proteins function as molecular switches inside the cells.

Correct choice is (a) True

Explanation: The COPII-coat selects and concentrates various PROTEINS for transport SING vesicles. Proteins selected by COPII-coated vesicles include glycosyltransferases which function at LATER STAGES in a biosynthetic PATHWAY.

The CORRECT option is (d) 0.5-1 μm

Explanation: The Golgi COMPLEX was discovered by CAMILLO Golgi for which he was AWARDED Nobel Prize in 1908. It CONSISTS of flattened, disk-like membranous cisternae of diameter 0.5 to 1 μm.

Correct CHOICE is (d) post-translationally

Explanation: Polypeptide is synthesized in the ribosome and if APPROPRIATE signal is present in its C-terminal it moves to the ER membrane during the synthesis, this is called co-translational MOVEMENT. In post-translational movement, the nascent polypeptide reaches the ER membrane after complete synthesis. Unlike mammalian cells post-translational movement of the POLYPEPTIDES is observed in the yeast cells.

Correct option is (a) Cell-free systems

To elaborate: Cell-free systems REFER to the ISOLATED organelles of the homogenized cells. These were FIRST used to COMPREHEND the protein synthesizing role of ribosomes and the protein sequestering role of endoplasmic reticulum membrane.

The correct answer is (b) LYSOSOME

To explain: After endocytosis materials REACH the LATE ENDOSOME, where the bound ligands are concentrated. After late endosome the materials reach lysosome for further processing.

The correct OPTION is (a) True

The explanation: There are two different types of receptors involved in the endocytosis. The endocytosis mediated by the SECOND group of receptors leads to their destruction, CALLED the receptor down regulation. This decreases the sensitivity of the cell towards further stimulation.

Correct answer is (a) Pinocytosis

The explanation: Pinocytosis, ALSO called bulk^–phase ENDOCYTOSIS is the non^–specific uptake of EXTRACELLULAR material. This process also removes PORTIONS of the plasma membrane and function in membrane recycling.

The CORRECT choice is (a) True

Explanation: Similar to LYSOSOMES present in the animal cells, plant cells CONTAIN vacuoles for intracellular digestion. Plant vacuoles have MANY of the same acid hydrolases as present in the lysosomes.

Right choice is (C) cytoplasmic structures

To elaborate: The cytoplasmic organelles of a cell namely endoplasmic reticulum, Golgi complex, lysosomes, vacuoles; TOGETHER represent the ENDOMEMBRANE system where individual components FUNCTION as a part of a COORDINATED unit.

Right option is (d) TRANSIT peptide

To explain I would SAY: The ‘stroma targeting peptide’ is located in the transit peptide SEQUENCE of the protein taken up by the chloroplast. This domain ensures the DELIVERY of the protein to stroma of the chloroplast.

The correct option is (B) LYSOSOME

The best I can explain: Mycobacterium tuberculosis is the agent responsible for tuberculosis. Following its phagocytosis, the BACTERIUM inhibits the fusion of phagosome with the lysosome, PREVENTING its deactivation in the cell.

The correct answer is (b) nucleus

The best I can EXPLAIN: The COMPLEX network of tubules and VESICLES is collectively known as endosomes. There are two classes of endosomes: early endosomes, located near the cell PERIPHERY, and late endosomes, located near the nucleus.

Right choice is (a) CLATHRIN

To EXPLAIN I would say: Substances bound to receptors enter a cell by receptor^–mediated endocytosis and collect in specialized domains of the plasma MEMBRANE called the ‘coated pits’. Clathrin is present on the electron^–dense coat of these pits.

Correct choice is (d) transport vesicles

Easiest EXPLANATION: The MATERIALS such as MEMBRANE proteins and other proteins are transported from the cis CISTERNAE to the TRANS cisternae by means of vesicles that bud from the rims of cisternae stack.

Right choice is (b) 2

The explanation: The heterogeneous similar sized membranous vesicles DERIVED from the endomembrane system of a homogenized cell, primarily REPRESENTED by the endoplasmic RETICULUM and Golgi COMPLEX, are referred to as microsomes.

Right CHOICE is (a) high H^+ concentration

Easy explanation: The receptors dissociate from their bound ligands as a result of high H^+ concentration in the early endosomes. FOLLOWING which they are concentrated into specialized tubular COMPARTMENTS representing the RECYCLING CENTERS of endosomes.

The CORRECT choice is (c) DIGITALIS

For explanation I would SAY: Digitalis is a toxic by-product stored in the plant cell VACUOLE, used to treat congestive heart failure and heart rhythm problems.

Right ANSWER is (a) lipid

The EXPLANATION is: RABS are G-proteins that recruit specific cytosolic tethering proteins to specific membrane surfaces. These are associated with MEMBRANES by a lipid anchor.

Right CHOICE is (a) True

The best I can EXPLAIN: The newly synthesized MEMBRANE and lysosomal proteins from the endoplasmic reticulum enter the Golgi complex through the cis face and reach the trans face, getting modified THROUGHOUT the way.

Right option is (b) False

Easy EXPLANATION: Endocytic pathway is the opposite of secretory pathway. In the endocytic pathway materials MOVE from the OUTER surface of the CELL to the cytoplasmic COMPARTMENTS like endosomes and lysosomes.

The correct choice is (a) ENDOPLASMIC reticulum

The best EXPLANATION: PROTEINS are synthesized in the endoplasmic reticulum and then modified in the Golgi complex. From the Golgi complex, the proteins are further transported to different DESTINATIONS DEPENDING upon their function and fate.

Right choice is (a) N-terminal

The explanation is: There are TWO LOCATIONS in a cell where a protein can be synthesized depending UPON its type and function. The signal that directs the SYNTHESIS of a protein to a FREE ribosome or ribosome attached to the endoplasmic reticulum is found in the C-terminal of the protein.

Correct option is (a) triskelion

To EXPLAIN: A MOLECULE of clathrin has THREE heavy and three light chains JOINED at the center, forming a three^–legged structure called triskelion.

Right ANSWER is (C) Proteins

The best I can explain: RNA interference phenomenon wherein cells PRODUCE small RNAs called the siRNAs that bind to mRNAs and INHIBIT the synthesis of proteins. RNAi is a strategy used by the researchers to INVESTIGATE the function of a missing protein.

Right OPTION is (B) regulatory

For explanation: The nerve cells secrete neurotransmitters in RESPONSE to an EXTRACELLULAR stimulus, the secretion is therefore termed as regulatory secretion.

The correct answer is (c) 6

To elaborate: Proteins can be delivered to the FOLLOWING SIX subcompartments of a chloroplast: INNER nd OUTER envelope membrane, intermembrane space, stroma, thylakoid membrane and thylakoid LUMEN.

Right OPTION is (c) AP2

The best I can explain: AP2 adaptor MOLECULES are associated with clathrin coated pits formed in the plasma membranes as a RESULT of receptor^–mediated ENDOCYTOSIS.

The CORRECT answer is (a) chaperones

The best explanation: For uptake into the mitochondria, PROTEINS must be presented to it in an unfolded STATE. MOLECULAR chaperones HSP 70 and Hsp 90 prepare the proteins for mitochondrial uptake by unfolding them.

Correct choice is (b) Jellyfish

The explanation is: The green FLUORESCENT protein is a protein synthesized by the jellyfish which is used to tag biological ENTITIES; for instance the gene synthesizing GFP can be COMBINED with the gene of test protein and the WHOLE BIOSYNTHETIC pathway of the protein can be traced.

Right CHOICE is (b) signal peptidase

For explanation: After the nascent polypeptide REACHES the CISTERNA of endoplasmic reticulum, it is ACTED upon by a VARIETY of enzymes. One such enzyme is signal peptidase which removes the hydrophobic signal sequence from the peptide.

The correct OPTION is (a) sorting SIGNALS

Explanation: Sorting signals ENCODED in amino acid sequence of PROTEINS or in the attached sugar MOLECULES are responsible for directing the proteins to their appropriate cellular destinations.

The correct choice is (a) vacuole

To EXPLAIN I would say: Vacuoles STORE MANY TOXIC compounds of the cell including by-products of metabolic pathways. Unlike animal cells, plant cells isolate the toxic by-products (by storing them in the vacuole) from the REST of the cell rather than discharging them.

The correct choice is (b) 2

The EXPLANATION is: There two models with contrasting VIEWS on the MOVEMENT of MATERIALS through the Golgi COMPLEX namely“Cisternal maturation model” and “Vesicular transport model”.

The correct ANSWER is (B) Oxygenases

To explain I would say: OXYGEN transferring enzymes – oxygenases (including cytochrome P450) carry out the detoxification of ORGANIC compounds and are synthesized in the smooth endoplasmic RETICULUM.

Correct OPTION is (c) muscle cells

Easiest EXPLANATION: Smooth endoplasmic RETICULUM sequesters calcium ions within the cytoplasm of the cell and CONTROLLED release of Ca^2+ from the SER of cardiac and skeletal muscle cells triggers contraction. Smooth endoplasmic reticulum (SER) in the AFOREMENTIONED cells is known as sarcoplasmic reticulum.

The CORRECT option is (a) N-terminus

Explanation: Mitochondrial matrix PROTEINS CONTAIN a removable sequence (presequence) containing a NUMBER of positively charged RESIDUES, located at the N-terminus.

The CORRECT choice is (B) turnover

Easy explanation: Organelle turnover, also CALLED AUTOPHAGY is the process of regulated DESTRUCTION and replacement of the cell’s own organelles. This function is performed by the lysosomes.

Right answer is (b) GTP-bound

Best EXPLANATION: The ‘RABS’ are encoded by over 60 diverse genes in humans and they cycle between two states; GTP-bound ACTIVE state and GDP-bound inactive state.

Correct option is (d) 0.5-1 μm

The EXPLANATION: The Golgi complex was discovered by CAMILLO Golgi for which he was awarded NOBEL Prize in 1908. It consists of flattened, disk-like membranous cisternae of DIAMETER 0.5 to 1 μm.